Computer Number system Note for IBPS PO

IBPS PO Notes for Computer Networking

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IBPS PO Notes for Computer Networking  

Computer Networking

There are two networking models-
  1.  OSI(Open System Interconnection) Model- It is developed by ISO (International Organization of Standardization). This is conceptual model which divides the communication process from sender to receiver into seven
  2. TCP/IP(Transmission control protocol and internet protocol) Model- This is the networking communication model that divides whole process of communication into four layer only. This protocol suite is result of the research and development conducted by DARPA (Defense Advanced Research Project Agency). OSI Model


Layer No. Layer Name and Name of Date called at different level  Protocols Device Used Tasks done by layer
Layer 7 Application
Layer (Data)
 –  Resource sharing,network
remote file
access etc.
Layer 6 Presentation Layer
 TBI,MPEG,S/MIME,TLS  –  Data Conversion,
Data Encryption,
character code
compresses data
Layer 5  Session Layer (Data)  NCP,PAP,SCP  –  This layer allows
maintenance and
security and
name recognition
and logging
Layer 4  Transport Layer
(Segment and Data-gram)
 UDP (Datagram) TCP(Segments )  –  This layer ensure
that data is send
error free,
sequentially with
no losses and
 Layer 3  Network Layer (Packets)  ICMP,IGMP,RIP, IPv4, IPv6  Router  Takes Routing
Logical Physical
Address Mapping
 Layer 2 Data Link Layer Frame

1) MAC Media
(Access Control) layer
2) LLC
(Logical Link Control) Layer

 Switches, Bridges, NIC  Provide error
Transmits and
 Layer 1 Physical Layer (Bits)  Modem,
Repeater, Hub,
unordered raw
stream over a

NIC (Network Interface Card) – It works on physical as well as Data link layer due to its dual functionality. NIC of a system is a place where its MAC address is stored. The NIC is built into motherboard of the system. This ensures each system in a network has different MAC address due to different NIC on different system.


Tr-transmission Media

Transmission media are used to convey information from one place to another. It can be classified into two types.
1) Guided Media
2) Unguided Media
Guided Media – Guided Media are the Media that are physical in nature means they provides physical path from sender to receiver and vice-versa. There are three types of Guided Media.
1) Twisted pair cable
2) Coaxial cable
3) Fiber optics cable
Twisted pair cable-
● In twisted pair cables there are two insulated copper wires that are twisted with
each other.
● In this media, data passed in the form of current.
● Less expensive
● Easy to Install
● Easy to expand
● Easily susceptible to interference and noise
● Attenuation is high
● Twisted pair cables oftenly used for small distances for example networking
within a building can be done by twisted pair cable.
● There are two types of twisted pair cable-
1) Shielded twisted pair cable
2) Un-shielded twisted pair cable
Coaxial Cable-
● There is a solid inner conductor (basically single copper wire) surrounded by
insulating material. Insulating material is surrounded by braided shield that is
further covered by outer sheath.
● Coaxial cable are used for long distance and supports many nodes in a single
● Less susceptible to interference and crosstalk than twisted pair cable.
● Efficient for long transmission.
● Example- TV signals transmission.
● Attenuation is low as compare to twisted pair cable.

Fiber Optic cable-
● Fiber optic cables are constructed by glass or plastic inner core surrounded by
cladding. Cladding is further covered by specially designed jacket.
● Small in size and weight
● Expensive than coaxial cable and twisted pair.
● In this media data travels in the form of lights.
● Suitable for secured and long transmission
● This media is not vulnerable to electrical interference, impulse noise or crosstalk.
● Attenuation is low for fiber optical cable.
● Best for the connectivity of LANs.

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Unguided Media- Unguided Media is the media in which for data transmission, no physical path is used. All the data transmits in the form of waves through air or water. There are two types of unguided media.
1) Radio Transmission
2) Microwaves Transmission
Radio Transmission-
● In Radio Transmission data is traveled in the form of radio waves through air.
● Radio, TV, Mobile phones uses radio transmission
● These signals can penetrate walls and entire building.
● They can be used for short transmission as well as long transmission.
● Its frequency is between 10KHz to 1 GHz
● Simple to install
● It has high Attenuation
● Mostly used for multicast communication
Microwave Transmission-
● It uses electromagnetic waves for data transmission
● It travels at high frequency i.e. 1 GHz to 30 GHz.
● It requires the sender to be insight of the receiver
● Mostly used for unicast communication
● There are two types of Microwave Transmission
1) Terrestrial Microwave
2) Satellite Microwave
● Very Costly
● Used for long distance telephone communication and carries thousands of voice channels together

Data Transmission Modes

(A) Based on the number of bits transmitted at a time- Serial Transmission- When data is transferred one after the other i.e. serially, it is called serial transmission. In this transmission single bit is transmitted at a time.
● Less Costly
● Throughput is less
● Low in speed
● Best for long distances

Parallel Transmission- In this transmission several bits transmitted over multiple lines simultaneously.
● High in speed
● Throughput is higher
● Costlier than Serial transmission
● Restricted to small distance transmission

(B) Based on the direction of data transmission/flow- There are 3 modes of data transmission-
1) Simplex
2) Half Duplex
3) Full Duplex
● When in data transmission there is only one sender and another is receiver.
Sender cannot be act as receiver and a receiver cannot be act as a sender.
● Data transmits in one direction only.

2) Half Duplex- In this transmission, data is transmitted in both direction but one at a single time.

3) Full duplex- In this transmission data can be transmitted in both direction simultaneously.

(B) Based on how the data will travel/flow on the transmission media- Asynchronous Serial Transmission / Synchronous Transmission-
Asynchronous Transmission- In Asynchronous transmission, data is transmitted one bit at a time, usually in the groups of characters. Each series of bits encapsulated with start and stop bit. In this transmission, media is fully dedicated to sender and receiver. The sender can-send data any time.
Synchronous Transmission- In this transmission data is transmitted serially by providing control characters at the beginning and the end of a message. In this transmission, media is not dedicated to sender and receiver all the time.When
the sender wants to send data then only transmission media is used.
Different Topology of Networks

Bus Topology-
● In Bus topology, different nodes within a network are connected together
through a common linear bus(cable).
● In this topology, transmission mode is half duplex means communicating devices
can be sender or receiver both but can send data only one at a time.

● Easy to connect a computer or other peripheral devices.
● Less Expensive.
● Works well in small area.
● Entire network gets shut down if there is break in main cable.
● Large amount of packets, collisions the network which may leads to high amount
of packets loss.
● Easy to understand
● Easy to expand
● Slower than ring topology

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Star Topology-
● In Star Topology, All nodes within the network are connected to the central node which work as a hub or switch for all nodes.
● More Expensive due to usage of large number of cables.
● If one cable breaks down then only one node will not work and other nodes will work as they are working before.
● It is normally connected with bus topology to make a hybrid network.
● Hub acts as a repeater for flow of data
● Easy to Setup, Modify and troubleshoot
● Installation cost is high

Ring Topology-
● In Ring topology each node is connected with two other nodes within the same network.
● This topology used large number of Repeaters.
● The transmission is unidirectional but it can be made bidirectional using two cables.
● Installation cost is low.
● Easy to Expand.
● In this topology data is transferred serially one bit at a time.
● Troubleshooting is difficult
● Failure one computer disturb the whole network.
● Deleting or adding nodes, cause the disturbance in the network activity

Mesh Topology – In Mesh topology a single node is connected with all other nodes available in the same network.
● There are two techniques to transmit data over the network.
1) Flooding
2) Routing
● There are two types of Mesh topology
1) Partial Mesh topology
2) Fully Mesh topology
● It is robust.
● Not Flexible
● Fault can be identified easily.
● Provides Privacy and Security.
● Most Expensive
● Cabling cost is more.
● Installation and Configuration is difficult.

Tree Topology-
● In this topology, there is one root node and all other nodes connected to it in the form of hierarchy that’s why it is also called as Hierarchical topology.
● Used in Wide area network.
● If root nodes fails then entire networks fails.
● Costly
● Maintenance is difficult.
● Addition of nodes is easy

Hybrid Topology – It is a combination of two or more typologies.

● Inherits the advantage and disadvantage of the typologies that is included in the network.
● It is Flexible.
● Reliable as error detecting is easy.
● Costly
● Complex in design
● Size can be increased easily.
● Effective

IBPS PO Notes for Computer Networking  Question and Answer

Q1. ________________ is not a web browser.
1. FOXPRO                2. Mozilla            3.Netscape navigator               4.Internet explorer

Answer (1)

Q2. Which one of the following is similar to sending an email?
1. Creating a drawing               2.Picturing an event               3.Narrating a story             4.Writinga letter

Answer (4)

Q3. It is the one which provides the facility of exchanging information between computing devices and is a combination of hardware and software.
1. Digital device                   2.Network            3.Peripheral             4.Expansion board

Answer (2)

Q4. The resources to all the computers in network are provided by the server which is a computer and they are connected by
1. Client               2.Mainframe             3.Network                      4.Supercomputers

Answer (3)

Q5. What is the use of video conferencing?
1. It is used for communication purpose                      2. It is used for liveconferencing                                                                       3. It is used to talk to each other                                   4.All of the above

Answer (2)

Q6. Which one of the following is the most important or powerful computer in a network?
1. Network station            2.Network client         3. Network Server                4.Desktop

Answer (3)

Q7. The connection of network which can only be attached to is
1. Intranet           2.Internet                  3. Extranet                    4.Virtual private network

Answer (1)

Q8. What is the term used for talking on net with the help of typed text?
1. New group       2. E-mail           3.Chatting              4.None of the above
Answer (3)

Q9.The internal network of a company is very large and would like to subnet into smaller parts. From the options given below, the device that will not be used to separate LAN and still protect critical resources is
1. The modem between computers         2. A router between subnet         3.An internal firewall         4. A switch between departments
Answer (1)

Q10. A small single site network is nothing but a
1. RAM      2. MAN          3.DSL            4.LAN

Answer (4)

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